Restore samplers' state across virtualized GL contexts.

gpu/command_buffer/service/context_state.cc

Index: gpu/command_buffer/service/context_state.cc
diff --git a/gpu/command_buffer/service/context_state.cc b/gpu/command_buffer/service/context_state.cc
index 5aa24fbacd095e7c09ea022d30254b49588ba9fe..aa5fe7271cc36e702455c666291dc24a690e4e77 100644
--- a/gpu/command_buffer/service/context_state.cc
+++ b/gpu/command_buffer/service/context_state.cc
@@ -281,6 +281,23 @@ void ContextState::RestoreTextureUnitBindings(
   }
 }
 
+void ContextState::RestoreSamplerBinding(GLuint unit,
+                                         const ContextState* prev_state) const {
+  if (!feature_info_->IsES3Capable())
+    return;
+  const scoped_refptr<Sampler>& cur_sampler = sampler_units[unit];
+  GLuint cur_id = cur_sampler ? cur_sampler->service_id() : 0;
+  GLuint prev_id = 0;
+  if (prev_state) {
+    const scoped_refptr<Sampler>& prev_sampler =
+        prev_state->sampler_units[unit];
+    prev_id = prev_sampler ? prev_sampler->service_id() : 0;
+  }
+  if (!prev_state || cur_id != prev_id) {
+    glBindSampler(unit, cur_id);
+  }
+}
+
 void ContextState::PushTextureDecompressionUnpackState() const {
   glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 
@@ -369,11 +386,12 @@ void ContextState::RestoreActiveTexture() const {
   glActiveTexture(GL_TEXTURE0 + active_texture_unit);
 }
 
-void ContextState::RestoreAllTextureUnitBindings(
+void ContextState::RestoreAllTextureUnitAndSamplerBindings(
     const ContextState* prev_state) const {
   // Restore Texture state.
   for (size_t ii = 0; ii < texture_units.size(); ++ii) {
     RestoreTextureUnitBindings(ii, prev_state);
+    RestoreSamplerBinding(ii, prev_state);
   }
   RestoreActiveTexture();
 }
@@ -496,7 +514,7 @@ void ContextState::RestoreGlobalState(const ContextState* prev_state) const {
 }
 
 void ContextState::RestoreState(const ContextState* prev_state) {
-  RestoreAllTextureUnitBindings(prev_state);
+  RestoreAllTextureUnitAndSamplerBindings(prev_state);
   RestoreVertexAttribs();
   RestoreBufferBindings();
   RestoreRenderbufferBindings();